Control device and work management system using same

ABSTRACT

A control device is provided with a communication unit and a processing unit. The communication unit makes communication with a tool that is used for the work of fastening a fastener (for example, a screw) and with an image pickup unit for capturing an image of the work site where the work is being performed. The processing unit executes a determination process of determining whether or not the work is being performed normally on the basis of the fastening torque applied to the fastener by the tool and the image captured by the image pickup unit.

TECHNICAL FIELD

The present invention relates generally to a control device and a workmanagement system and, more particularly, to a control device formanaging a work using a tool and a work management system using thesame.

BACKGROUND ART

Conventionally, in a work of fastening (tightening) a fastener such as abolt to a predetermined position on a target object, there is known afastening management system or fastening tool provided with a device ormechanism for preventing an omission of fastening (see, e.g., PatentDocument 1). The fastening management system according to PatentDocument 1 includes a torque wrench serving as a fastening tool and amanagement device for managing fastening position information.

The torque wrench outputs a fastening torque, which is applied to fastenthe fastener, to the management device through wireless communication.Further, the torque wrench specifies a fastening position based onsignals outputted from an acceleration sensor, a gyro sensor and ageomagnetic sensor when the torque wrench has been moved. Then, thetorque wrench outputs fastening position information indicating thefastening position to the management device via, e.g., a wirelesscommunication medium. The management device acquires the fasteningtorque and the fastening position information outputted from the torquewrench via a communication medium to thereby manage the acquiredfastening torque and fastening position information.

Patent Document 1: Japanese Unexamined Patent Application PublicationNo. 2013-188858

However, in the conventional example, although it is possible toperceive a position where the worker fastens the fastener by using thetool (i.e., a position where the work using the tool is done by theworker), it is impossible to check a state of the work using the tool,which is problematic. For example, even though the worker thinks thatthe fastener has been fastened, actually, the fastener may not befastened correctly. In this case, it is impossible to check whether ornot the fastener has been fastened correctly and successfully (i.e., thestate of the work using the tool) in the above conventional example.

SUMMARY OF THE INVENTION

In view of the above, the present invention provides a control devicecapable of checking a state of a work using a tool and a work managementsystem using the control device.

In accordance with an embodiment of the present invention, there isprovided a control device including: a communication unit configured tomake communication with a tool used during a work of fastening afastener and further make communication with an image pickup unitconfigured to capture an image of a working site where the work isperformed; and a processing unit configured to execute a determinationprocess of determining whether or not the work is being performedsuccessfully based on a fastening torque applied to the fastener by thetool and the image captured by the image pickup unit.

In accordance with another embodiment of the present invention, there isprovided a work management system including: the control devicedescribed above; the tool including a communication unit configured totransmit data of the fastening torque to the control device; and awearable device including a communication unit configured to transmitdata of the image pickup unit and the captured image to the controldevice.

With such configuration, it is possible to check a state of the workusing the tool.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram of a control device and a workmanagement system according to an embodiment.

FIG. 2 is a schematic diagram showing an example of the work managementsystem according to the embodiment.

FIG. 3 is a schematic diagram showing an example of a tool in the workmanagement system according to the embodiment.

FIG. 4 is a schematic diagram showing another example of the tool in thework management system according to the embodiment.

FIG. 5 is a flowchart showing an operation of the work management systemaccording to the embodiment.

FIGS. 6A and 6B respectively show a state in which a screw is tightenedcorrectly and a state in which the screw is tightened incorrectly in thework management system according to the embodiment.

FIG. 7A is a schematic diagram of a part management system and FIG. 7Bis a schematic block diagram of the part management system to which thework management system according to the embodiment is applied.

DETAILED DESCRIPTION

As shown in FIGS. 1 and 2, a control device 2 according to an embodimentof the present invention includes a communication unit 23 and aprocessing unit 24. The communication unit 23 makes communication with atool 3 which is used in a fastening work using a fastener (e.g., a screw10) as well as an image pickup unit 41 for capturing an image of aworking site where the fastening work is carried out. The processingunit 24 executes a process of determining whether or not the fasteningwork is being performed normally based on a fastening torque applied tothe fastener by the tool 3 and an image captured by the image pickupunit 41.

Further, as shown in FIGS. 1 and 2, a work management system 1 accordingto the embodiment of the present invention includes the control device2, the tool 3 and a wearable device 4. The tool 3 includes acommunication unit which transmits data on the fastening torque to thecontrol device 2. The wearable device 4 includes the image pickup unit41 and a communication unit 43 which transmits data on the capturedimage to the control device 2.

Hereinafter, the control device 2 and the work management system 1according to the present embodiment will be described in detail.However, the following configurations described below are only examplesof the present invention, and the present invention is not limited tothe following embodiments. Thus, it will be understood by those skilledin the art that various changes and modifications may be made withoutdeparting from the scope of the present invention.

As shown in FIG. 1, the work management system 1 of the presentembodiment includes the control device 2, the tool 3 and the wearabledevice 4. The work management system 1 further includes a host device 5which makes communication with the control device 2.

The control device 2 includes a display unit 21, a storage unit 22, thecommunication unit 23 and the processing unit 24. The display unit 21 isformed of, e.g., a liquid crystal display, an organic EL(electro-luminescence) display or the like and is configured to displayvarious information such as instructions for a worker W1 by using atleast one of a message and an image. In the control device 2 of thepresent embodiment, the display unit 21 is formed of a touch panel-typeliquid crystal display.

The storage unit 22 includes, e.g., an electrically erasableprogrammable read-only memory (EEPROM), a flash memory or the like andis configured to store various information such as applications whichare operated by the processing unit 24. Further, the storage unit 22stores, for each working site, data on the fastening torque transmittedfrom the tool 3 and data on the image captured by the wearable device 4.Besides, the storage unit 22 stores, for each working site, a torque(target torque) required when fastening the fastener, data on an image(instruction image) representing the working site where the work needsto be done by the worker W1, and an image (reference image) showing anormal state where the fastener is tightened properly. Here, thefastener is a member such as the screw 10 (see FIG. 6A) or a bolt.

An example of data stored in the storage unit 22 is shown in Table 1.Table 1 shows data for a case where the worker W1 tightens the screw 10as the fastener. In Table 1, “No.” is the number assigned to eachworking site where the work is to be done by the worker W1. Further,“Standard” represents a nominal size (e.g., ‘M8’, ‘M10’, etc.) of thefastener required for each working site.

TABLE 1 Target Fastening Stan- Torque Instruction Torque ReferenceCaptured No. dard (N · m) Image (N · m) Image Image 1 M8 20 ± 10% A(1)19.8 B(1) C(1) 2 M10 40 ± 10% A(2) 39.6 B(2) C(2) . . . . . . . . . . .. . . . . . . . . . N − 1 M8 20 ± 10% A(N − 1) 18.5 B(N − 1) C(N − 1) NM10 40 ± 10% A(N) 40.5 B(N) C(N)

The communication unit 23 is formed of a communication module incompliance with wired and wireless communication standards (e.g.,Bluetooth (registered trademark) and WiFi (registered trademark)). Inthe control device 2 of the present embodiment, the communication unit23 makes wireless communication with the tool 3 and the host device 5,and makes wired communication with the wearable device 4 via a cable CA1(see FIG. 2). However, the communication unit 23 may make wirelesscommunication with the wearable device 4 and may make wiredcommunication with the tool 3 and the host device 5 via respectivecables (not shown).

The processing unit 24 includes, e.g., a CPU (central processing unit),and executes various processes by operating the applications stored inthe storage unit 22. Specifically, the processing unit 24 executes aprocess of transmitting an instruction signal to the wearable device 4by reading out the data on the instructions from the storage unit 22.Further, the processing unit 24 executes a process of determiningwhether or not the fastening work is being performed successfully by theworker W1 based on a fastening torque applied to the fastener by thetool 3 and an image captured by the image pickup unit 41. Thedetermination process will be described in detail later. The controldevice 2 of the present embodiment is formed of a tablet-type portableelectronic device as shown in FIG. 2. Therefore, the control device 2 isexcellent in convenience since it can easily be carried by the worker W1while the work is performed. However, the control device 2 is notlimited to the tablet-type portable electronic device.

For example, the control device 2 may be formed of a smartphone.Alternatively, the control device 2 may be formed of a programmablelogic controller (PLC), a personal computer (PC) or the like. Further,the control device 2 preferably includes at least the communication unit23 and the processing unit 24, and optionally includes the display unit21 and the storage unit 22. For example, instead of the display unit 21,the control device 2 may be provided with an audio output unit (notshown) for outputting voice instructions about the work to the workerW1. Alternatively, the control device 2 may include both of the displayunit 21 and the audio output unit.

The tool 3 is configured to apply a predetermined torque to the fastenerso as to tighten the fastener to a workpiece 11 (see FIG. 6A). Here, theworkpiece 11 is a target object, such as a wood plate or an iron plate,on which the work (in this case, the work of tightening the fastener) isdone. As shown in FIG. 1, the tool 3 includes a measuring unit 31configured to measure the fastening torque applied to the fastener andthe communication unit 32 configured to make communication with thecontrol device 2.

The tool 3 may be, e.g., a torque wrench, an electric impact driver orthe like. An electric impact wrench may be another example of the tool3. Further, the impact driver and the impact wrench may be operated by,e.g., compressed air power other than electric power. Alternatively, thetool 3 may be a manual screwdriver. In any example of the tool 3, thetool 3 necessarily includes the communication unit 32, but may notnecessarily include the measuring unit 31. If the tool 3 does not havethe measuring unit 31, the tool 3 may transmit, as the fastening torque,a setting torque set by a torque limiter (which will be described later)to the control device 2.

Hereinafter, a torque wrench 300 and an impact driver 310 will bebriefly described as examples of the tool 3 with reference to FIGS. 3and 4.

The torque wrench 300 includes a head 301, an arm 303, a grip 304 and acase 308 as shown in FIG. 3. The arm 303 includes therein amagnetostrictive load cell (detecting unit) 305. The case 308 includestherein a CPU (torque calculating unit) 306 and a communication I/F(interface) 307.

The head 301 is a member serving as a rotation center when the fasteningwork is performed by the worker W1. At the head 301, a socket insert 302to which a socket 302A is affixed is provided. The socket 302A is amember into which the fastener such as a bolt is fitted. By rotating thehead 301 in a state where the fastener is fitted into the socket 302Awhile the socket 302A is affixed to the socket insert 302, it ispossible to apply a predetermined torque to the fastener. In otherwords, the socket 302A corresponding to the nominal size of the fasteneris mounted to the head 301, and the torque is applied to the fastenerthrough the socket 302A by the rotation of the head 301. Further, at thesocket insert 302, the socket 302A corresponding to the nominal size ofthe fastener may be appropriately affixed.

The grip 304 is a member gripped by the worker W1 when fastening thefastener. The grip 304 has a shape such that it can be easily gripped bythe worker W1. The arm 303 is a rod-shaped member which transfers theforce applied to the grip 304 to the fastener through the head 301. Thearm 303 includes therein a torque limiter (not shown).

The torque limiter is a mechanism which is operated when a torqueapplied to the fastener reaches a preset torque value to prevent anexcessive torque from being applied to the fastener. Since the torquelimiter is a conventionally known mechanism, a detailed descriptionthereof will be omitted. Further, the preset torque causing the torquelimiter to be operated can be set by, e.g., an adjustment knob (notshown). The adjustment knob is also well known in the art, a detaileddescription thereof will be omitted.

The load cell 305 includes a strain gauge (not shown). The load cell 305is slightly deformed depending on the torque applied whenever fasteningthe fastener. The load cell 305 measures a strain due to the deformationby using the strain gauge and outputs an electrical signal proportionalto the strain to the CPU 306. That is, the load cell 305 outputs anelectric signal corresponding to the torque applied to the fastener. TheCPU 306 calculates a fastening torque based on the electric signaloutputted from the load cell 305. That is, in the torque wrench 300, theload cell 305 and the CPU 306 correspond to the measuring unit 31.

The communication I/F 307 is formed of a communication module incompliance with the wireless communication standard (e.g., Bluetooth(registered trademark)). Here, the communication I/F 307 is configuredto transmit a signal including data of the fastening torque calculatedby the CPU 306 to the control device 2 through wireless communicationusing an antenna (not shown). That is, in the torque wrench 300, thecommunication I/F 307 corresponds to the communication unit 32.Alternatively, the communication I/F 307 may be configured to transmitthe signal including the data of the fastening torque calculated by theCPU 306 to the control device 2 through wired communication using acable (not shown).

Further, the torque wrench 300 may include a liquid crystal display (notshown), which is exposed on one surface of the case 308, to displayinformation about the fastening torque and the like. With suchconfiguration, the worker W1 is able to check the fastening torqueimmediately.

The impact driver 310 includes an impact mechanism 311, a motor 312, anoutput shaft 314, a magnetostrictive torque sensor 316 (first detectingunit), an acceleration sensor 315 (second detecting unit) and a controlcircuit 317 (torque calculating unit) as shown in FIG. 4. Further, theimpact driver 310 includes a cylindrical body 318 (body part) and a grip319 which protrudes in a direction (downward in FIG. 4) intersecting anaxial direction of the output shaft 314 from a circumferential surfaceof the body 318.

At one end of the grip 319 (a lower end of the grip 319 in FIG. 4), abattery pack 320 including a resin case and a rechargeable battery 321accommodated in the resin case is detachably attached. The impact driver310 is operated by electric power supplied from the rechargeable battery321. Specifically, the impact driver 310 is operated by supplying theelectric power from the rechargeable battery 321 to each of the motor312 and the control circuit 317 through electric wires 323 and 324.

Further, the grip 319 is provided with an operation lever 325 which canbe pushed in by the worker W1. A switch circuit (not shown) ismechanically connected to the operation lever 325. When the operationlever 325 is pushed in by the worker W1, the switch circuit outputs anoperation signal to the control circuit 317.

The impact mechanism 311 is coupled to a shaft 313 of the motor 312. Theimpact mechanism 311 is configured to generate a pulse-like impact forceaccording to the rotation of the shaft 313 and apply the generatedimpact force to the output shaft 314. That is, the impact mechanism 311generates the pulse-like impact force. The motor 312 is formed of, e.g.,a brushed DC (Direct Current) motor or a brushless DC motor. The motor312 is accommodated in the body 318 such that the shaft 313 coincideswith an axis of the body 318. A driving current is supplied to the motor312 from the control circuit 317 through the electric wire 324. Further,an RPM (revolutions per minute) and a rotational speed of the shaft 313of the motor 312 are controlled by the control circuit 317.

The output shaft 314 is rotatably attached to one end (left end in FIG.4) of the body 318 so as to coincide with the axis of the body 318. Theoutput shaft 314 is configured to be rotated by the impact force appliedfrom the impact mechanism 311. At a front end of the output shaft 314, abit 314A corresponding to the nominal size of the fastener such as thescrew 10, a bolt or the like is affixed. By fitting the bit 314A intothe fastener while the bit 241A is affixed to the output shaft 314, itis possible to apply a predetermined torque to the fastener by using theimpact driver 310. That is, the bit 314A corresponding to the nominalsize of the fastener is affixed to the output shaft 314, and the outputshaft 314 is rotated by the impact force applied from the impactmechanism 311.

The torque sensor 316 is configured to measure, in a non-contact manner,a strain generated in the output shaft 314 by the torque applied to theoutput shaft 314 when fastening the fastener. Then, the torque sensor316 outputs an electrical signal proportional to the strain to thecontrol circuit 317 through an electric wire 322. That is, the torquesensor 316 measures a torque applied to the output shaft 314.

The acceleration sensor 315 is attached to a groove (not shown), whichis formed by carrying out D-shaped cutting at a portion of the outputshaft 314 for example. The acceleration sensor 315 is configured todetect at least one of an angular velocity of the output shaft 314 and acircumferential acceleration of the output shaft 314. The accelerationsensor 315 may further detect a radial acceleration of the output shaft314 in addition to the circumferential acceleration of the output shaft314.

Further, a pair of communication coils (not shown) are provided at theoutput shaft 314 to supply electric power to the acceleration sensor 315and to transmit a detected value of the acceleration sensor 315 to thecontrol circuit 317. One (first communication coil) of the communicationcoils is fixed to the circumferential surface of the output shaft 314.The other one (second communication coil) of the communication coils isformed in a cylindrical shape and the output shaft 314 passes through acenter thereof. The second communication coil is arranged to face thefirst communication coil.

When the control circuit 317 supplies AC current to the secondcommunication coil, the AC current flows through the first communicationcoil by the mutual induction. The acceleration sensor 315 converts theAC current flowing through the first communication coil into DC currentand stores charges in, e.g., a capacitor (not shown) to thereby ensurean operating power. Further, the acceleration sensor 315 transmits thedetected value to the control circuit 317 through the secondcommunication coil and the electric wire 322 by supplying a pulse signalhaving a frequency different from that of the AC current inputted fromthe control circuit 317 to the first communication coil.

The control circuit 317 includes a microcomputer (microcontroller) and acommunication module in compliance with the wireless communicationstandard (e.g., Bluetooth (registered trademark)). The control circuit317 has a function of controlling the rotation of the shaft 313 of themotor 312 based on the operation signal outputted from the switchcircuit in response to the pushing operation of the operating lever 325.

In the impact driver 310, the control circuit 317 calculates thefastening torque on the basis of an inertia torque of the output shaft314 and the bit 314A calculated based on the detected value of thetorque sensor 316 and the detected value of the acceleration sensor 315.That is, in the impact driver 310, the torque sensor 316, theacceleration sensor 315 and the control circuit 317 correspond to themeasuring unit 31. Further, the control circuit 317 has a function ofstopping the operation of the motor 312 when the calculated fasteningtorque reaches a preset torque value.

Further, the control circuit 317 has a function of transmitting a signalincluding data of the calculated fastening torque to the control device2 through wireless communication using an antenna (not shown). That is,in the impact driver 310, the control circuit 317 corresponds to thecommunication unit 32. Alternatively, the control circuit 317 may beconfigured to transmit the signal including data of the calculatedfastening torque to the control device 2 through wired communicationusing a cable (not shown).

The wearable device 4 is constituted by attaching the image pickup unit41 and the display unit 42 to a device, e.g., glasses, a goggle or ahelmet to be mounted on the head of the worker W1. In the workmanagement system 1 of the present embodiment, the wearable device 4 isconstituted by a glasses-type device as shown in FIG. 2 and includes theimage pickup unit 41, the display unit 42, the communication unit 43 andthe processing unit 44 as one unit.

The image pickup unit 41 is formed of, e.g., a CCD (charge-coupleddevice) image sensor or CMOS (complementary metal oxide semiconductor)image sensor. The capturing range of the image pickup unit 41 issubstantially equal to the display range of the display unit 42, andalso is substantially equal to the field of view of the worker W1 towhom the wearable device 4 is attached. Therefore, the image pickup unit41 can capture a range approximate to the field of view of the workerW1. Further, since the capturing range of the image pickup unit 41 doesnot exactly coincide with the field of view of the worker W1,preferably, correction processing may be performed on the captured imageso as to make the capturing range equal to the field of view of theworker W1. Further, as shown in FIG. 6A, the image pickup unit 41captures an image so that the captured image is viewed from a directionperpendicular to an installation surface of the workpiece 11 (workingsite) (i.e., a direction perpendicular to the plane of FIG. 6A).Further, the “perpendicular” may not be exactly “perpendicular” in thestrict sense.

The display unit 42 is formed of, e.g., a head-mounted display (HMD) orthe like and is configured to display various information for the workerW1 by using at least one of the message and the image. The head-mounteddisplay may be a projecting type display which enable observation of theimage by forming a virtual image by using a half mirror or the like, ormay be a projecting type display which forms an image directly on theretina by using the lens of the eyes.

The communication unit 43 is formed of a module in compliance with thewired communication standard and is configured to make communicationwith the control device 2 through the cable CA1. The communication unit43 may be formed of a module in compliance with the wirelesscommunication standard (e.g., Bluetooth (registered trademark). In thiscase, the communication unit 43 makes wireless communication between thecontrol device 2 and the wearable device 4.

The processing unit 44 includes, e.g., a CPU and is configured torealize various processes by executing programs. Specifically, theprocessing unit 44 executes a process of capturing an image of theworking site by using the image pickup unit 41 based on an instructionsignal transmitted from the control device 2. Further, the processingunit 44 executes a process of displaying instruction contents for theworker W1 on the display unit based on data included in the instructionsignal transmitted from the control device 2. Additionally, theprocessing unit 44 executes a process of transmitting data of the imagecaptured by the image pickup unit 41 to the control device 2.

The host device 5 is constituted by, e.g., a programmable logiccontroller (PLC), a personal computer (PC), a server and the like. Thehost device 5 has a function of communicating with the control device 2.In the work management system 1 of the present embodiment, the controldevice 2 makes wireless communication with the host device 5 through awireless access point 51 (see FIG. 2) included in the host device 5.Further, the host device 5 has a function of collectively managing datatransmitted from the control device 2. Specifically, the host device 5stores, for each work, data of the captured image and data of thefastening torque transmitted from the control device 2 to thereby managethe history of the works performed by the worker W1.

A timing of transmitting data to the host device 5 from the controldevice 2 may be arbitrarily set. For example, the control device 2 mayregularly transmit data to the host device 5, or may transmit data tothe host device 5 at the time when all of the works are completed.Alternatively, the control device 2 may transmit data to the host device5 when the control device 2 receives a request for data transmissionfrom the host device 5.

Hereinafter, an operation of the work management system 1 of the presentembodiment will be described with reference to FIG. 5. First, when theworker W1 manipulates the control device 2 to start the work, theprocessing unit of the control device 2 executes a process oftransmitting an instruction signal including data of the work to thewearable device 4 (step S1). Alternatively, the processing unit 24 ofthe control device 2 may be triggered to execute the step S1 by theworker's manipulation on one of the tool 3 and the wearable device 4.

The processing unit 44 of the wearable device 4, upon receiving theinstruction signal, executes a process of projecting (displaying) dataof an instruction image representing the working site included in theinstruction signal and other instruction data required for the work(e.g., the standard fastening torque and the nominal size of the screw10) on the display unit 42 (step S2). The worker W1 identifies theworking site by looking at the instruction image projected on thedisplay unit 42. Further, the worker W1 makes preparations for the workusing the tool 3 by looking at the instruction data (step S3). Forexample, when the tool 3 is the impact driver 310, the worker W1installs the bit 314A corresponding to the nominal size of the screw 10on the output shaft 314 or sets the setting torque.

Next, the worker W1 manipulates the image pickup unit 41 of the wearabledevice 4. This manipulation allows the processing unit 44 to execute aprocess of capturing an image of the working site and an area around theworking site through the image pickup unit 41 (step S4). At this time,the worker W1 may adjust a position of the image pickup unit 41 prior tothe capturing process, for example, by moving his/her head, such thatthe working site is positioned at the center of the field of view.Further, in the case of displaying a frame defining the capturing rangeon the display unit 42, the worker W1 may adjust the position of theimage pickup unit 41, for example, by moving his/her head such that theworking site is positioned in the frame. Then, the processing unit 44executes a process of transmitting data of the captured image to thecontrol device 2.

The processing unit 24 of the control device 2, upon receiving the dataof the captured image, executes a process of checking whether or not theworker W1 would work in a correct working site by comparing the capturedimage with the instruction image of the working site stored in advance(step S5). In this checking process, for example, a similarity isevaluated by comparing the data of the captured image with the data ofthe instruction image. Then, it is determined as normal (that is, theworker W1 would work in a correct working site) if the evaluatedsimilarity is equal to or greater than a predetermined threshold, and itis determined as abnormal (that is, the worker W1 would work in a wrongworking site) if the evaluated similarity is smaller than thepredetermined threshold. If it is determined as normal (YES in step S5),the processing unit 24 executes a process of transmitting to thewearable device 4 a start signal instructing the worker W1 to start thework (step S6).

Here, the “similarity” may be a digitized parameter indicative of thedegree of similarities between the data of the captured image and thedata of the instruction image. For example, a difference image betweenthe captured image and the instruction image is obtained, and thesimilarity may be evaluated based on the number of pixels which havegray values smaller than a predetermined value in the difference image.Alternatively, for example, a difference image between the capturedimage and the instruction image is obtained and a binary image isobtained by binarizing the difference image. Then, labels are assignedto regions in the binary image and the similarity may be evaluated basedon an area of each labeled region.

If it is determined as abnormal (NO in step S5), the processing unit 24executes a process of transmitting to the wearable device 4 a signalinstructing the worker W1 to capture an image of the working site again.Then, the sequence of the steps S1 to S5 is repeated until it isdetermined that the worker W1 would work in a correct working site.

The processing unit 44 of the wearable device 4, upon receiving thestart signal, executes a process of projecting on the display unit 42 animage or a message of urging the worker W1 to start the work (step S7).The worker W1 starts the work using the tool 3 by looking at the imageor the message projected on the display unit 42 (step S8). In thisexample, the worker W1 performs the task of tightening the screw 10 tothe workpiece 11 by using the tool 3. In this case, the measuring unit31 of the tool 3 measures the fastening torque applied to the screw 10when tightening the screw 10. Once the work is completed, thecommunication unit 32 of the tool 3 performs a process of transmittingdata of the fastening torque measured by the measuring unit 31 to thecontrol device 2 (step S9).

Upon receiving the data of the fastening torque, the processing unit 24of the control device 2 determines that the work by the worker W1 hasbeen completed. Then, the processing unit 24 executes a process oftransmitting, to the wearable device 4, a signal instructing the workerW1 to capture an image of the working site after the work (step S10).Upon receiving this instructing signal, the processing unit 44 of thewearable device 4 executes a process of projecting on the display unit42 an image or a message of urging the worker W1 to capture an image ofthe working site after the work.

The worker W1 manipulates the image pickup unit 41 by looking at theimage or the message displayed on the display unit 42. This manipulationallows the processing unit 44 to execute a process of capturing an imageof the working site and an area around the working site through theimage pickup unit 41 (step S11). At this time, similarly to the step S4,the worker W1 may adjust a position of the image pickup unit 41 prior tothe capturing process, for example, by moving his/her head. Then, theprocessing unit 44 executes a process of transmitting data of thecaptured image to the control device 2.

Further, although the worker W1 captures an image of the working siteand the area around the working site by manipulating the image pickupunit 41 in the steps S4 and S11, the capturing process may be performedautomatically by the image pickup unit 41. For example, the image pickupunit 41 may automatically capture an image of the working site when theworking site is positioned inside the frame displayed on the displayunit 42.

The processing unit 24 of the control device 2, upon receiving the dataof the captured image, executes a process of determining whether or notthe work has been performed normally (successfully) based on thefastening torque acquired in advance and the data of the captured image(step S12). If it is determined as normal (YES in step S13), theprocessing unit 24 determines that the work in the current working sitehas been completed, and executes a process of transmitting aninstruction signal for the next working site to the wearable device 4.If it is determined as abnormal (NO in step S13), the processing unit 24executes a process of transmitting an instruction signal for the work tobe performed successfully to the wearable device 4. Then, the sequenceof the steps S6 to S13 is repeated until it is determined that the workby the worker W1 is performed successfully. Further, the sequence of thesteps S1 to S13 is repeated until the work is completed for each andevery working site.

In this example, if it is determined as abnormal in the step S13, theprocessing unit 24 of the control device 2 instructs the worker W1 toperform the same working task again. However, this instruction isoptional, and it may be also possible for the processing unit 24 toinstruct, after the work is completed for each and every working site,the worker W1 to perform the same working task again only for eachunsuccessful work.

Hereinafter, the determination process in step S12 will be described inmore detail. First, the processing unit 24 of the control device 2executes a process of comparing the fastening torque transmitted fromthe tool 3 with a target torque. For example, for the work correspondingto “No. 1” of Table 1, the fastening torque measured by the tool 3 is19.8 (N·m), which is within a range of the target torque of 20±10%(N·m). Therefore, in this case, the processing unit 24 determines thatthe screw 10 is sufficiently tightened. On the other hand, if thefastening torque is not within the range of the target torque, theprocessing unit 24 determines it as abnormal (that is, the work has beenperformed unsuccessfully).

Meanwhile, even though the fastener (here, the screw 10) is sufficientlyfastened, it does not surely mean that the work has been performednormally. For example, as shown in FIG. 6A, when the screw 10 is notinclined with respect to the workpiece 11 (working site) as viewed froma direction perpendicular to an installation surface of the workpiece 11(i.e., a direction perpendicular to the plane of FIG. 6A), it can bedetermined that the screw 10 has been tightened correctly (that is, thework has been performed successfully). On the other hand, as shown inFIG. 6B, when the screw 10 is inclined with respect to the workpiece 11as viewed from the direction perpendicular to the installation surfaceof the workpiece 11, it can be determined that the screw 10 has not beentightened correctly (that is, the work has been performedunsuccessfully). Further, the “perpendicular” may not be exactly“perpendicular” in the strict sense.

Therefore, when it is determined that the fastener has been sufficientlyfastened, the processing unit 24 executes a process of comparing data ofthe captured image with data of a reference image. For example, in thisprocess, similarly to the step S5, a similarity is evaluated bycomparing the data of the captured image with the data of the referenceimage. Then, it is determined as normal (that is, the work has beenperformed successfully) if the evaluated similarity is equal to orgreater than a predetermined threshold, and it is determined as abnormal(that is, the work has been performed unsuccessfully) if the evaluatedsimilarity is smaller than the predetermined threshold. For example, forthe work corresponding to “No. 1” of Table 1, when the similarityevaluated by comparing data C(1) of the captured image with data B(1) ofthe reference image is equal to or greater than the predeterminedthreshold, the processing unit 24 determines it as normal (that is, thescrew 10 has been fastened correctly to the workpiece 11). On the otherhand, when the evaluated similarity is smaller than the predeterminedthreshold, the processing unit 24 determines it as abnormal (that is,the screw 10 has not been fastened correctly to the workpiece 11).

Further, in the determination process, the processing unit 24 maydetermine whether or not a diameter of the head 100 of the screw 10matches up with its standard (e.g., ‘M8’, ‘M10’ and the like) bycomparing the data of the captured image with the data of the referenceimage. For example, when a M8 screw is accidentally fastened in aworking site where a M10 screw has to be fastened, the determination ofthe processing unit 24 is made as abnormal. Therefore, the processingunit 24 can determine whether or not the screw 10 of the standardappropriate for the working site is fastened.

Further, in the determination process, when the fastening torque has anabnormal value excessively greater than the target torque, theprocessing unit 24 may determine that there is an abnormality in themeasuring unit 31 of the tool 3. In this case, by notifying the workerW1 of the abnormality occurred in the measuring unit 31 of the tool 3through the tool 3 or the wearable device 4, it can be urged to repairor replace the tool 3.

Further, in the determination process, the processing unit 24 acquiresthe fastening torque regularly from the tool 3 during a time period(work period) from the start to the end of the work, and may determinewhether or not the fastening work is successfully performed on the basisof data of the time series. For example, when the fastening torque issubstantially constant in this work period, the processing unit 24 candetermine that the fastening work has been performed successfully. Onthe other hand, when the fastening torque varies discontinuously in thework period, the processing unit 24 can determine that the fasteningwork has been performed unsuccessfully.

As described above, in the control device 2 and the work managementsystem 1 of the present embodiment, it is determined whether or not thework by the worker W1 is being performed normally based on the fasteningtorque applied by the tool 3 to the fastener and the captured image ofthe working site taken by the image pickup unit 41. Accordingly, thecontrol device 2 and the work management system 1 of the presentembodiment can check whether or not the fastener has been fastenedsuccessfully (i.e., a state of the work using the tool 3). Therefore,with the control device 2 and the work management system 1 of thepresent embodiment, it is possible to improve work efficiency byproviding appropriate instructions to the worker W1 depending on thestate of the work. Furthermore, with the control device 2 and a workmanagement system 1 of the present embodiment, it is also possible toreduce mistakes made by the worker W1 by checking the state of the work.Thus, there is an advantage that it is possible to improve the qualityof a product made through the work.

In particular, in the control device 2 of the present embodiment, theprocessing unit 24 obtains the similarity in the determination processby comparing the captured image with the reference image showing thestate in which the fastener is fastened normally in the working site.Further, the processing unit 24 determines whether or not the work isbeing performed normally based on the comparison result between thefastening torque and the target torque required for the work and thecomparison result between the similarity and the predeterminedthreshold. With such configuration, it is possible to more accuratelycheck whether or not the fastener has been fastened successfully. Thisconfiguration may be optionally employed.

Further, in the control device 2 of the present embodiment, uponreceiving the data of the fastening torque, the processing unit 24determines that the work by the worker W1 has been completed. Then, theprocessing unit 24 may execute a process of transmitting, to thewearable device 4, a signal instructing the worker W1 to capture animage of the working site after the work. Upon receiving thisinstructing signal, the image pickup unit 41 of the wearable device 4may automatically capture an image of the working site. In other words,in the control device 2 of the present embodiment, the image capturingtiming of the image pickup unit 41 may be determined by using the signalfrom the tool 3 as a trigger. In this configuration, the image captureof the image pickup unit 41 is performed at the timing when the workerW1 completes the work using the tool 3. Therefore, there is an advantagethat it is possible to capture an image of the working site without theuse of the hands of the worker W1. This configuration may be optionallyemployed.

Further, the control device 2 of the present embodiment includes thedisplay unit 21 configured to display instructions about the work forthe worker W1 by using at least one of a message and an image. In thisconfiguration, it is possible to visually show the instructions to theworker W1. This configuration may be optionally employed.

Further, in the control device 2 of the present embodiment, the capturedimage is an image when the working site is viewed from the directionperpendicular to the installation surface. Therefore, the control device2 can determine whether the fastener is fastened in the directionperpendicular to the installation surface, and thus it can be easilydetermined whether the fastener is fastened correctly on theinstallation surface. This configuration may be optionally employed.

Further, in the work management system 1 of the present embodiment, thewearable device 4 includes the display unit 42 configured to displayinstructions about the work for the worker W1 transmitted from thecontrol device 2 by using at least one of a message and an image.Therefore, in this work management system 1, the worker W can easilycheck the instructions about the work by simply orienting his/her eyesto the wearable display unit 42. This configuration may be optionallyemployed.

Further, in the work management system 1 of the present embodiment, itis preferable that the tool 3 is the torque wrench 300 having the head301, the load cell (detecting unit) 305 and a CPU (torque calculatingunit) 306. In this configuration, it is possible to obtain a fasteningtorque by measuring a torque actually applied to the fastener from thetool 3. Therefore, it can be accurately determined whether the work hasbeen performed successfully. The use of the torque wrench 300 as thetool 3 is optional.

The tool 3 may be the impact driver 310 having the impact mechanism 311,the output shaft 314, the magnetostrictive torque sensor 316 (firstdetecting unit), the acceleration sensor 315 (second detecting unit),and the control circuit 317 (torque calculating unit). Also in thisconfiguration, it is possible to obtain a fastening torque by measuringa torque actually applied to the fastener from the tool 3. Therefore, itcan be accurately determined whether the work has been performedsuccessfully. The use of the torque wrench 300 as the tool 3 isoptional.

Further, in the work management system 1 of the present embodiment, thewearable device 4 is a device to be mounted on the head of the worker W1such as protective glasses, a goggle, or a helmet. In thisconfiguration, since the field of view of the worker W1 is substantiallythe same as the capturing range of the image pickup unit 41, it isadvantageous in that it is easy to capture an image of the working site.Further, in this configuration, since the information such as theinstructions about the work is projected on the display unit 42 presentin the field of view of the worker W1 without being aware of it, it isadvantageous in that the worker W1 can easily perform the work, andhardly overlooks the instructions about the work. This configuration maybe optionally employed.

Further, in the work management system 1 of the present embodiment, atleast one of the wearable device 4 and the control device 2 may have afunction of outputting voice instructions about the work for the workerW1. In this configuration, it is possible to provide the instructionsabout the work to the worker W1 through auditory communication. Thus,the work can be easily performed since the worker W1 does not need tointerrupt the work. This configuration may be optionally employed.

Further, the work management system 1 of the present embodiment includesthe host device 5. The host device 5 stores, for each work, the data ofthe captured image and the data of the fastening torque transmitted fromthe control device 2. In this configuration, by using the host device 5,it is possible to manage the history of the works performed by theworker W1. Thus, it is advantageous in that the work management and thequality control can be easily carried out together.

Furthermore, in the work management system 1 of the present embodiment,the host device 5 may store information about devices (e.g., the tool 3and the wearable device 4) electrically connected to the control device2. The information about each device may include, e.g., correctiveinformation of various parameters of the device, position information ofthe device, information of the worker W1 handling the device,information of the time at which the work using the device is performedand the like. In this configuration, not only the fastening torque foreach work can be managed, but also the devices connected to the controldevice 2 and the worker W1 handling the work can be managed. Thus, thework management can be carried out in a more detailed manner. Forexample, in this configuration, it is possible to change a working planto more precisely perform the work by referring to the history ofworking hours or the working skill of the worker W1 handling the device.Further, in this configuration, it is also possible to provideindividual guidance, such as reading a working manual, to the worker W1with low working skill.

It is optional for the work management system 1 to include the hostdevice 5. If the work management system 1 does not include the hostdevice 5, it is preferable that the storage unit 22 of the controldevice 2 stores the data of the fastening torque, the data of thecaptured image and the information about devices for each work. Withthis configuration, the control device 2 can have the same function asthat of the host device 5.

Meanwhile, the work management system 1 of the present embodiment may beused in conjunction with a part management system 6 shown in FIGS. 7Aand 7B. The part management system 6 is a system used in a so-calledcell production method of taking parts P1 out sequentially from aplurality of part boxes 71 and assembling the extracted parts P1according to a predetermined production plan. As shown in FIGS. 7A and7B, the part management system 6 includes a shelf 7 consisting of theplurality of part boxes 71, a plurality of display devices 8respectively mounted on the part boxes 71 in a one-to-one relationship,and a work platform 9 where the worker W1 performs the work. In each ofthe part boxes 71, the parts P1 are arranged. Different types of partsP1 may be disposed in the respective part boxes 71. Alternatively, thesame type of parts P1 may be disposed in some of the part boxes 71. Inthe part management system 6, the control device 2 of the presentembodiment controls the plurality of display devices 8.

The display devices 8 are electrically connected to the control device 2by cables (not shown). Each of the display devices 8 is configured to beturned on in response to a signal transmitted from the control device 2.The control device 2 is configured to turn on one of the display devices8 according to the predetermined production plan to urge the worker W1to take out the parts P1 from the part box 71 corresponding to theturned-on display device 8. Further, each of the display devices 8 isprovided with a switch (or a lever) 81 operable by the worker W1. Eachdisplay device 8 can be turned off by manipulating the switch 81 by theworker W1 in a state in which the display device 8 is turned on.

Hereinafter, an operation of the control device 2 in the part managementsystem 6 will be described in detail. The processing unit 24 of thecontrol device 2 determines, based on a signal outputted from onedisplay unit 8 by manipulating the switch 81, that a part P1 has beenextracted from a part box 71 corresponding to the display unit 8. Whenit is determined that the part P1 has been extracted, the processingunit 24 executes a process of transmitting to the wearable device 4 asignal instructing the worker W1 to capture an image of the extractedpart P1. Upon receiving the above instruction signal, the processingunit 44 of the wearable device 4 executes a process of projecting on thedisplay unit 42 an image or a message of urging the worker W1 to capturean image of the extracted part P1.

The worker W1 manipulates the image pickup unit 41 by looking at theimage or the message projected on the display unit 42. By thismanipulation, the processing unit 44 executes a process of capturing animage of the extracted part P1 through the image pickup unit 41.Alternatively, the processing unit 44 may execute a process ofautomatically capturing an image of the extracted part P1 through theimage pickup unit 41 upon receiving the signal from the control device2. Then, the processing unit 44 executes a process of transmitting dataof the captured image to the control device 2.

The processing unit 24 of the control device 2, upon receiving the dataof the captured image, executes a process of checking whether or not theworker W1 has extracted a correct part by comparing the captured imagewith a reference image of the part P1 stored in advance. In other words,the processing unit 24 executes a process of determining whether or notthe correct part P1 is extracted from any one of the plurality of thepart boxes 71 by comparing the captured image of the extracted part P1obtained by the image pickup unit 41 with the reference image of thepart P1 stored in advance. In this process, for example, a similarity isevaluated by comparing the data of the captured image with the data ofthe reference image of the part P1. Then, it is determined as normal(that is, the worker W1 has extracted a correct part P1) if theevaluated similarity is equal to or greater than a predeterminedthreshold set in advance, and it is determined as abnormal (that is, theworker W1 has extracted an incorrect part P1) if the evaluatedsimilarity is smaller than the predetermined threshold.

If it is determined as normal, the processing unit 24 executes a processof turning on a display device 8 corresponding to a part box 71 in whicha part P1 to be extracted subsequently is accommodated. If it isdetermined as abnormal, the processing unit 24 executes, e.g., a processof flickering a display device 8 corresponding to a part box 71 in whicha correct part P1 is accommodated, or a process of transmitting to thewearable device 4 a signal instructing the worker W1 to extract acorrect part P1.

In this configuration, it is advantageous in that the control device 2can manage the work of assembling the extracted part P1 (in thisembodiment the work of fastening the fastener) together with the work ofextracting the part P1 in the previous step. Further, in thisconfiguration, if it is determined in the determination process that theworker W1 has extracted an incorrect part P1, the control device 2notifies the worker W1 of the determination result, thereby urging theworker W1 to extract a correct part P1.

In the control device 2 and the work management system 1 of the presentembodiment, the determination process is performed for the work offastening the fastener. However, the determination process may beperformed for other working tasks. For example, in a case where adrilling work is to be performed on the workpiece 11, the tool 3transmits data of a torque applied to the workpiece 11 during thedrilling work to the control device 2. Further, the image pickup unit 41captures a working site where a hole is formed after the drilling work.Then, the processing unit 24 of the control device 2 executes a processof determining that the hole formed in the workpiece 11 has a sufficientsize if the torque transmitted from the tool 3 exceeds a target torque.Further, the processing unit 24 obtains a similarity by comparing dataof the captured image with data of a reference image, and executes aprocess of determining whether or not the hole has been correctly andsuccessfully drilled into the workpiece 11 by comparing the similaritywith a threshold set in advance.

Further, in the work management system 1 of the present embodiment, theimage pickup unit 41 is provided in the wearable device 4. However, theimage pickup unit 41 may be provided in the tool 3, for example. In thiscase, the tool 3 may have a function of executing a process of capturingan image of the working site by using the image pickup unit 41 based onan instruction signal transmitted from the control device 2 and aprocess of transmitting data of the image captured by the image pickupunit 41 to the control device 2.

Further, in the work management system 1 of the present embodiment,although the wireless communication using Bluetooth (registeredtrademark) is performed between the control device 2 and the host device5, the wireless communication using the wireless communication standardsuch as WiFi (registered trademark), ZigBee (registered trademark) orthe like may be performed therebetween. Further, the mobilecommunication standard such as LTE (long term evolution) for mobiledevices may be used for the wireless communication between the controldevice 2 and the host device 5. The wireless communication using themobile communication standard is particularly effective, for example,when the control device 2 is installed outdoors and the worker W1performs work outdoors.

Further, it is particularly preferable that the wireless communicationis performed by using the mobile communication standard for mobiledevices because established services, which are provided through themobile network, such as location-based service using GPS (globalpositioning system) and a weather forecast, can also be used. That is,in this case, since the location of the control device 2 can bespecified by the GPS, it becomes possible for the host device 5 tomanage the locations of the control device 2 and the worker W1. Further,it is possible to check the environment (e.g., hot and humid climate) ofan area where the control device 2 is located through the weatherforecast. Therefore, it is possible for the host device 5 to estimateand manage the lifetime of the devices including the tool 3 and thewearable device 4 according to the use environment of the control device2.

Further, in the work management system 1 of the present embodiment, thetool 3 may be a battery-operated device (e.g., the impact driver 310)using a rechargeable battery (secondary battery) 321. In thisconfiguration, a cable between the tool 3 and a power source, or a cablebetween the tool 3 and a compressed air source (air compressor) becomesunnecessary. Thus, the worker W1 can easily handle the tool 3 withoutregard to cables.

Further, in the work management system 1 of the present embodiment, thecontrol device 2 is configured to control a single tool 3 and a singlewearable device 4. However, the control device 2 may be configured in adifferent way. For example, the control device 2 may be configured tocontrol each of a plurality of sets, each including the tool 3 and thewearable device 4. Further, in the work management system 1 of thepresent embodiment, the host device 5 is configured to makecommunication with a single control device 2. However, the host devicemay be configured to make communication with each of a plurality ofcontrol devices 2.

1. A control device comprising: a communication unit configured to makecommunication with a tool used during a work of fastening a fastener bya worker and further make communication with an image pickup unitconfigured to capture an image of a working site where the work isperformed; and a processing unit configured to execute a determinationprocess of determining whether or not the work is being performedsuccessfully based on a fastening torque applied to the fastener by thetool and the image captured by the image pickup unit.
 2. The controldevice of claim 1, wherein the processing unit obtains, in thedetermination process, a similarity by comparing the captured image witha reference image showing a state in which the fastener is successfullyfastened in the working site, and the processing unit determines whetheror not the work is being performed successfully based on a comparisonresult between the fastening torque and a target torque required for thework and a comparison result between the similarity and a threshold setin advance.
 3. A work management system comprising: the control deviceof claim 1; the tool including a communication unit configured totransmit data of the fastening torque to the control device; and awearable device including a communication unit configured to transmitdata of the image pickup unit and the captured image to the controldevice.
 4. The work management system of claim 3, wherein the wearabledevice further includes a display unit configured to displayinstructions about the work for the worker transmitted from the controldevice by using at least one of a message and an image.
 5. The workmanagement system of claim 3, wherein the tool is a torque wrenchincluding: a head to which a socket corresponding to a nominal size ofthe fastener is affixed, the head being rotated to apply a torque to thefastener through the socket; a detecting unit configured to output anelectric signal corresponding to the torque applied to the fastener; anda torque calculating unit configured to calculate the fastening torquebased on the electric signal.
 6. The work management system of claim 3,wherein the tool is an impact driver including: an impact mechanismconfigured to generate a pulse-like impact force; an output shaft towhich a bit corresponding to a nominal size of the fastener is affixed,the output shaft being rotated by the impact force applied from theimpact mechanism; a first detecting unit configured to detect a torqueapplied to the output shaft; a second detecting unit configured todetect at least one of an angular velocity of the output shaft and acircumferential acceleration of the output shaft; and a torquecalculating unit configured to calculate the fastening torque on a basisof an inertia torque calculated based on a detected value of the firstdetecting unit and a detected value of the second detecting unit.
 7. Thework management system of claim 3, wherein the wearable device is adevice to be mounted on the worker's head.
 8. The work management systemof claim 3, wherein at least one of the wearable device and the controldevice is configured to output voice instructions about the work for theworker.
 9. The work management system of claim 3, further comprising ahost device configured to make communication with the control device,wherein the host device stores, for each work, data of the capturedimage and data of the fastening torque transmitted from the controldevice.
 10. The work management system of claim 9, wherein the hostdevice stores information about devices electrically connected to thecontrol device.
 11. The work management system of claim 3, wherein in apart management system including a plurality of part boxes eachcontaining parts and a plurality of display devices mounted on the partboxes in a one-to-one relationship, the control device is configured toturn on one of the display devices according to a progress status of awork of extracting the parts to urge the worker to extract a part fromthe part box corresponding to said one of the display devices, and theprocessing unit further executes a process of determining whether or nota correct part has been extracted from the part box corresponding tosaid one of the display devices by comparing an image of the extractedpart captured by the image pickup unit with a reference image of thepart stored in advance.